The present invention relates to soles for shoes, and more particularly, relates to a sole unit for an athletic shoe.
When running, a person pushes off on the toe of their foot, arcs their foot through the air and sets their foot down on the ground in front of their body. For most athletes, their heel strikes first, and their foot pronates slightly as they roll forward onto the ball of the foot. The process is then repeated by pushing off on the ball of their foot or toes. This heel-to-toe motion is common among athletes. When the heel strikes the ground, significant impact forces are created that must be attenuated by the athlete and shoes. Without proper cushioning mechanisms built into the shoe, these impact forces can create acute or overuse injuries. Further, forces are generated along various axes of the shoe. Without proper stability mechanisms, injury or loss of athletic performance are possible.
To lessen an athlete""s potential injury by reducing the impact upon the athlete, a shoe must attenuate impact. Since the impact force is the overall force divided by time of force application, the most efficacious method of absorbing shock is by extending the time of force application, and thereby lessening the peak force upon the athlete. This can be done, for example, by allowing for travel in the heel as it strikes the ground. This curtails the amount of shock communicated to the athlete""s body.
Some prior art shoes address the problem of shock absorption by using a variety of micro-cellular foams, gels or air bladders, which offer minimal travel. Softer soles provide more cushion and shock absorption, but in so doing compromise the angular stability of the foot. Conversely, firmer soles better stabilize the foot, but provide commensurately less shock absorption. In conventional shoes, the cushioning foams, gels, air bladders and such play a dual role in providing a platform for stabilizing the foot.
The present invention provides a sole unit for a shoe having superior stability and shock absorption properties in a sole unit design that can be customized for different applications and body-type characteristics. The sole unit provides discrete components for addressing stability and shock absorption needs. In addition, the present invention provides a high performance sole unit having superior durability.
In one embodiment of the present invention, the sole unit includes a directional element operable to provide flexibility in a longitudinal direction of the sole unit and to provide stiffness in a lateral direction of the sole unit. The sole unit further includes a cushioning element operably coupled to the directional element. The cushioning element is operable to absorb an impact force applied to the directional element.
In another embodiment of the present invention, the directional element is adapted to be connected to an upper of a shoe and includes a top member, a bottom member, and at least one resiliently flexible strut member therebetween. The strut member supports the top member a spaced distance away from the bottom member.
In still another embodiment of the present invention, the sole unit includes a directional element having a top member, a bottom member, and a plurality of spaced apart resiliently flexible strut members. The strut members extend between the top and bottom members from the medial side to the lateral side of the sole unit for supporting the top member a spaced distance away from the bottom member. The sole unit further includes a plurality of cushioning members adapted to be received by the directional element. The cushioning members are operable to absorb an impact force applied to the top or bottom member.
In yet another embodiment of the present invention, the sole unit is incorporated into a shoe by being coupled to the shoe upper. The sole unit includes a directional element having a top member, a bottom member, and a plurality of spaced apart resiliently flexible strut members. The strut members extend between the top and bottom members from the medial side to the lateral side of the sole unit. The strut members support the top member a spaced distance away from the bottom member. The sole unit further includes a plurality of cushioning members adapted to be received by the directional element between the strut members. The cushioning members are operable to absorb an impact force applied to the top or bottom member.